1. Field of the Invention
The present invention is related to a rotary combustor, or incinerator, for incinerating waste material in a combustion barrel and, more particularly, to an improvement in the generally cylindrical side wall of the combustion barrel for directing air supplied to the combustor to provide more efficient combustion.
2. Description of the Related Art
Proper disposal of solid waste has become an increasingly serious problem as existing sites for land disposal reach or approach capacity and new sites become increasingly difficult to locate. Incineration of combustible solid waste has long been used to reduce the quantity of solid matter needing disposal. However, existing methods of incineration often result in incomplete combustion and produce exhaust gases which include carbon monoxide and unburned hydrocarbons.
One device used to incinerate solid waste is a water-cooled rotary combustor which has been used in an increasing number of applications for the last one to two decades. Examples of water-cooled rotary combustors are described in U.S. Pat. Nos. 3,882,651 to Harris et al.; 4,066,024 to O'Connor; and 4,226,584 to Ishikawa, all of which are hereby incorporated by reference. A general description of a rotary combustor is provided immediately below and a more detailed description will be provided later.
As illustrated schematically in a cross-sectional side elevation view in FIG. 1, a water-cooled rotary combustor generally includes a combustion barrel 10 having a general cylindrical side wall 23 affixed to annular support bands 13 which are received on rollers 12 to permit rotation of the barrel 10 about its longitudinal axis. The barrel 10 has a generally open input end 16 for receiving material to be burned, such as municipal solid waste 14 which varies in moisture content and heating value. A second or opposite end 18 of the barrel 10 is disposed in a flue 28. Exhaust gases 20 and solid combustion products 22, i.e., ash, exit the combustion barrel 10 at the exit end 18. The barrel 10 is cooled by cooling pipes 24 joined by gas-porous interconnections 51, having opening 52, formed on a generally cylindrical side wall 23 of the barrel 10. Combustion gas, typically air, is supplied by windboxes, e.g., 32, 34 and 36, to the interior of the barrel 10 through the openings 52 to support the combustion of the waste material 14.
As illustrated in FIG. 2A, the rotation of the barrel 10 causes the waste material 14 to shift to one side with the result that combustion occurs primarily along one side of the barrel 10. However, the air which is supplied in a conventional combustor is not always directed towards the area of combustion, as indicated by air flow arrow 41. This results in less efficient combustion than would otherwise be possible.